Rectifier



Dec. 21, 1937, JACKSON ET 2,102,713

RECTIFIER Filed Oct. 50, 1933 Patented Dec. 21, 1937 PATENT OFFICE RECTIFIER John G. Jackson, Detroit, Grosse Pointe Farms,

and Stanley M. Hanley, Mich., assignors, by

mesne assignments, to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application October 30, 1933, Serial No. 695,904

9 Claims.

The invention relates to rectifiers and more particularly to that type in which commercial alternating current from supply limes is transformed and rectified to deliver direct current at a predetermined voltage and which is maintained as nearly constant as possible. In the present state of the art various rectifiers of this character have been devised, but difiiculty has been encountered in maintaining the desired uniformity in operation. This is due, first, to variations in voltage in the A. C. supply line and second, to variations in load in the D. C. circuit. The usual method of correction for these variations is by placing a variable impedance reactance in the A. 0. circuit which is controlled by excitation coils in the D. C. circuit. It is also usual t divide the D. C. windings into two equal parts which are so connected as to cancel out A. C. components which may be induced from A. C. windings in the reactance. While such constructions de control D. C. voltage to a certain extent, they are nevertheless unsatisiactory for many uses. Thus a considerable degree of instability has been found to exist in the output voltage due to unbalance between parts of the reactor circuits With resultant hunting or oscillation at low period in the output voltage. It has also been iound difiicult to secure the desired characteristics in the voltage curve of the output circuit due in a large measure to substantial differences in the effect of the regulating means resulting from unavoidable variations in commercial manufacture, such as quality of the iron or steel used in the magnetic circuit and particularly in slight variation in gaps between the sections of the magnetic circuit.

It is the object of the present invention to obtain a construction of rectifier of the general type above described, but which is free from the defects inherent in constructions heretoiore used. To this end the invention consists in the construction as hereinaiter set forth.

In the drawing:

Fig. 1 is an end elevation of one specific construction of my improved rectifier;

Fig. 2 is an electrical diagram of the construc tion illustrated in Fig. 1;

Figs. 3 and 4 are diagrams illustrating modified constructions;

Fig. 5 is an elevation of the adjustable resistor.

As illustrated in Figs. 1 and 2, A is a step-down transformer, the primary coil A of which is connected into an A. C. circuit B. 0 is a rectifier of any suitable construction but preierably of the copper oxide type. D is a magnetic reactance impedance including an impedance coil D connected in the A. C. circuit B and a pair of balanced coils D D which are in series With each other and included in the direct current circuit E et the rectifier. The coils D D are also connected so as to cancel induced currents in the one by that in the other.

With the construction thus far described, variations in load in the D. C. circuit of the device, corresponding ordinarily to variations in the external load supplied, will cause variations in the D. C. excitation of the magnetic circuit of the reactance by means of coils D and Dwith.resulting increased reactance in coil D when the D. C. current values are decreased and decreased reactance in the coil D when the D. C. current is increased. When the variable reactance device With its component parts is suitably proportioned the effect upon the impedance of coil D resulting from the load circuit variation may ce such as to closely compensate for variations in voltage drop in the rectifying device which w0uld otherwise adversely affect the output voltage. Self-regulation or compensation of voltage by this means may be made to affect output voltage, not only in such manner as to correct normal voltage variations but to effect certain predetermined characteristics such as the establishment of a lower no load output voltage than the normal full load voltage at the output terminals.

As previously stated, we find a tendency t0 oscillate at certain load values in a circuit constituted as previously described, and we therefore associate With the cooperating elements of the variable or regulating reactance coils HH of Fig. 3 and similar coils KK of Fig. 4, such pairs of coils being closed upon themselves preferably through an adjustable resistance F 01 suitable value, such that a suitable damping effect tending to suppress the oscillation will be set up by current flow within the resulting local circuit. It is possible also by varying resistor settings in this arrangement to influence the effectiveness of the regulating reactors at diiiering load values. We may also establish a local circuit for the suppressing cf oscillations resulting from the employment of the regulating device by connecting the outer terminals of the coils D D together through a suitable resistor F, Fig. 2, meterably of adjustable resistance value.

This latter arrangement we find to serve a double purpose as the resistor when so connected serves not only to establish the local circuit for the damping of oscillations but serves also to having contact portions F by-pass a portion of the D. C. load circuit so that the eifectiveness of the reactance controlling D. C. coils D D may be determined by the setting of the resistance values in the included portion of the resistor. The ability to thus readily vary the contrclling affect of the D. C. circuit upon the variable reactance is especially important due to the necssity for the correction by convenient means of manufacturing variations above re- 7 ferred to. The employment of this feature also permits difiering results to be secured :from standard equipment when desired.

With each of the modifications above referred to, a condenser L may or may not be connected in parallel across the output terminals of the rectifier.

With the specifi construction illustrated in Fig. 1, M is a base plate on one end of which is mounted on posts N a choke coil O. Above this choke coil is mounted the transformer A and above this transformer the insulator plate P for the mounting of electrical connections. On the opposite end of the base plate M is mounted the condenser L and in the central portion of the plate is mounted the magnetic reactance impedance D. Q is a bracket extending upward from the base in rear of the element D on which is mounted a rectifier C of the copper oxide type, while mounted in rear of this bracket is the adjustable resistorF. This as shown is a coil Wound upon an insulator core and having an ex- 7 terior. coating of insulating material cut away from* one side. F and F are clamping bands engaging the exposed portion of the coil. These bands may be adjusted in position to vary the resistance and form the electrical connections for including the resistor in the circuit.

Dry plate rectifiers and in particularthose of the copper oxide type have an aging characteristic Which results in loweringthe output D. C. Voltage in a marked degree after a period of use. To compensate for this, we provide the resistor F with a third terminal F for including in the shunt additional turns of the coil increasing the resistance. This portion is, however, initially short circuited and is only used after the aging of the rectifier. For convenience in making such adjustment, the terminals F and F are connected to leads extending to contacts on the terminal plate P and a short circuiting connector or 'jumper R. connects these contacts. Thus whenever necessary this jumper may be removed Which, by throwing additional resistance in the shunt, Will defiect a greater current volume through the reactor coils with consequent lessening of the impedance of the reactance under load, thus in efiect, in a simple and convenient way, compensating for loss of voltage of the device re sulting from a normal aging effect. It is evident of course that the value of the resistance to be introduced can be readily adjusted during manufacture and that more than a single sp may be sointroduced if desired.

What we claim as our invention is:

'1. A voltage regulating system comprising a rectifier adapted to be fed from a source of alternating current through an alternating current circuit, a regulating reactor in said alternating current circuit, said regulating reacto comprising a magnetic core, a magnetizing winding on said core, said magnetizing winding being energized in accordance with the load current output of said rectifier, and a single phase alternating current winding on said core and connected in said alternating current circuit, said alternatng current winding and said magnetizing winding being related to each other to neutralize alternating voltages induced in said magnetizing winding by said alternating current winding, and stabilizing means for said system comprising a resistance connected across said magnetizing winding and forming a local closed circuit there-' with. 7

2. A voltage regulating system comprising a rectifier adapted to be fed from a source of alternating current thrcugh an alternating current circuit, a regulating reactor in said alternating current circuit, said regulating reactor comprising a magnetic core, a magnetizing winding on said core, said magnetizing winding being energized in accordance with the load current output of saidrectifier, and a single phase alternating current winding on said core and connected in said alternating current circuit, said alternating current winding and saidmagnetizing winding being related to each other to neutralize alternating voltages induced in said magnetizing winding by said alternating current winding, stabilizing means for said system comprising a resistance connected across said magnetizing winding and forming a local closed circuit therewith, and means for varying said resistance for varying the degree of response of said magnetizing winding to said load current.

3. A Voltage regulating system comprising a rectifier adapted to be fed from a source of alternating current through an alternating curient circuit; a direct current load circuit for said rectifier, a regulating reactor in said alternating current circuit, said regulating reactor comprising a magnetic core, a magnetizing winding on said core, said magnetizing winding being connected in series with said direct current load circuit whereby said magnetizng winding is energized in accordance with the load current output of said rectifier, and a single phase alternating current winding on said core and connected in said alternating current circuit, said alternating current winding and said magnetizing winding being related to each other to neutralize alternatirig voltages induced in said magnetizing winding by said alternating current winding, and stabilizing means for said system comprising a resistance connected across said magnetizing winding and formng a local closed circuit therewith. V

4. A voltage regulating System comprising a rectifier adapted to be fed from a source of alternating current through an altrnating current circuit, a direct current load circuit for said rectifier, aregulating reactor in said alternating current circuit, said regulating reactor comprising a magnetic core, a magnetzirlg winding on said core, said magnetizing winding being connected in series with said direct current load circuit whereby said magnetizing winding is energized in accordance with the load current output of said rectifier, and a single phase alternating current winding on said-core and connected in said alternating current circuit, said alternating current winding and said magnetizing windingbeing related to each other to neutralize alternating voltages induced in said magnetizing winding by said alternating current winding, stabilizing means for said 'system comprising a resistance connected across said magnetizing winding and forming a local closed circuit therewith,

and means for Varying said resistance for varying the degree of response of said magnetizing winding to said load current.

5. A voltage regulating system comprising a rectifier adapted to be ied from a source of alternating current through an alternating cur rent circuit, a regulating reactor in said alternating current circuit, said regulating reactor comprising a magnetic ocre, magnetizing windings on said core, said magnetizing windings being encrgized in accordance With the load current output of said rectifier, alternating current windings on said ocre and connected in said alternating current circuit, and additional windings inductively associated With said magnetizing windings, and stabilizing means for said system comprising a resistance connected across said additional windings and forming a local closed circuit therewith.

6. A voltage regulating system comprising a rectifier adapted to be fed from a source of alterhating current through an alternating current circuit, a regulating reactor in said alternating current circuit, said regulating reactor comprising a magnetic ocre, magnetizing windings on said core, said magnetizing windings being encrgized in accordance with the load current output of said rectifier, alternating current windings on said ocre and connected in said alternating current circuit, and additional windings inductively associated with said manetizing windings, stabilizing means for said system comprising a resistance connected across said additional Windings and forming a local closed circuit therewith and means for varying said resistance.

7. A voltage regulating system comprising a. rectifier adapted to be fed from a source of al ternating current through an alternating current circuit, et direct current output circuit for said rectifier, a regulating reactor in said alternating current circuit, said regulating reactor comprising a magnetic core, a pair of direct current magnetizing windings on said ocre and connected in said direct current output circuit, said magnetizing windings being connected in series and arranged to cancel induction currents therein, a second pair of windings in inductive relation to said first pair, said second pair being connected in series in a closed circuit, and a resistor ci selected resistance in series with said second pair of windings.

8. A voltage regulating system comprising a rectifier subject to loss of voltage due to ageing and adapted to be fed from a source of alternating current through an alternating current circuit, a direct current output circuit for said rectifier, a regulating reactor in said alternating current circuit, said regulating reactor comprising a magnetic core, a pair of direct current magnetizing windings on said ocre and connected in said direct current output circuit, an adjustable resistor in shunt with said pair of windings, and a readily removable short-circuiting member for part of said resistor adapted by its removal to substantially compensate for ageing of said rectifier.

9. A voltage regulating system comprising a dry plate rectifier adapted to be fed from a source of alternating current through an alternating current circuit, et direct current output circuit for said rectifier, a regulating reactor in said alternating current circuit, said regulating reactor comprising a magnetic ocre, a pair of direct current magnetizing windings on said ocre and connected in said direct current output circuit, a resistor in shunt with said pair of windings adjustable for a selected resistance and having a portion of additional resistance, and means for normally short-circuiting said additional resistance, said last-named means being located in an accessible position and being removable to compensate for ageing of said rectifier, the regulating reactor and the direct current magnetizing windings being adapted in their normally constant relationship to decrease the impedance in the alternating current circuit upon increase of current in the direct current output circuit, and to increase the impedance in the alternating current circuit upon decrease of the current in the direct current output circuit from a value greater than the minimum.

JOHN G. JACKSON. STANLEY M. HANLEY. 

